First record of an adult Taningia danae (Cefalopoda: Octopoteuthidae) in the Canary Islands (Central-east Atlantic)

Abstract

The deep-sea hooked squid, Taningia danae Joubin, 1931 (Octopoteuthidae) is one of the largest oceanic squids, reaching dorsal mantle lengths (DML) of 1700 mm (Nesis 1982; 1987), and has been reported to weigh up to at least 161.4 kg (Roper & Vecchione 1993). This species is characterised by a conical mantle with large triangular fins that occupy almost the entire mantle length and its width exceeds up to 130% of the DML. This species has eight short robust arms, with two series of hooks on each arm, and arm pair II with two large oval terminal photophores, which are covered by black eyelidlike skin folds that allow for the controlled flashing of each photophore. Another pair of photophores is embedded on each side of the ink sac. Tentacles are robust on paralarvae but are lost at a dorsal mantle length of 40 to 45 mm (Jereb & Roper 2010). This species has a cosmopolitan distribution, being more abundant in tropical and temperate waters, but has also been observed in boreal areas, e.g. 57º N in the NE Atlantic. Paralarval and juvenile individuals of T. danae have been caught within Scottish waters (Santos et al. 2001), the North Atlantic Ocean (Clarke & Lu 1974; Okutani 1974; Lu & Clarke 1975), and off Bermuda, Cape Verde and the Madeira Islands (Roper & Vecchione 1993). In the Pacific Ocean the species has been reported from the Hawaiian Islands and New Zealand (Roper & Vecchione 1993) and in the Mediterranean Sea from Algerian waters (Quetglas et al. 2006). Santos et al. (2001) reported an incomplete adult female caught at 400 m depth by a commercial trawler in Galician waters. Posteriorly, González et al. (2003) recorded three specimens (two females and a mature male), in the Carrandi fishing ground (Cantabrian sea). A further large specimen (1600 mm ML) was captured at Georges Bank (USA) in the NW Atlantic (Roper & Vecchione 1993). Three living specimens have been video-recorded: two in the Ogasawara Islands’ waters (Japan), in the western North Pacific at 240 and 900 m depth (Kubodera et al. 2007) and one in the waters of the Azores (Seine Seamount) at 2717 m depth (Gomes-Pereira & Tojeira 2014). Despite the small number of catches of large individuals of T. danae, several hundred large beaks have been recorded from sperm whale (Physeter macrocephalus) stomach contents, suggesting that it is not a rare deep-sea squid species in tropical and subtropical oceans (e.g. Clarke et al. 1993; Smith & Witehead 2000; Evans & Hindell 2004; Clarke 2006). In the Canary Islands, previous records of T. danae come from beaks found in the stomach contents of three Cuvier's beaked whales (Ziphius cavirostris) stranded in Lanzarote and Fuerteventura in 2002 (Santos et al. 2007) and from the stomach contents of a sperm whale stranded in Fuerteventura in 2005 (Fernández et al. 2009). Later, Bordes et al. (2009) reported three juvenile individuals of 30-100 mm ML caught in mesopelagic trawling nets around Gran Canaria and on the south-eastern side of Fuerteventura in 2000 and 2002. This study reports the occurrence of the first adult deep-sea hooked squid in the Canarian archipelago. The studied specimen was collected off SW Tenerife, confirming the presence of all life stages of this species in Canary waters.